Motor-controlling device.



PATENTE'D JUNE 4, 1907.-

G. MIT IELSTRASS & A. FRANK.

MOTOR CONTROLLING DEVICE.

AIPLIOATION FILED 001217, 1906.

Inventors:

Carl mittelstrass, fflbrecht Frank,

UNITED A r Nr oFEICE.

CARL MITTELSTRASS, or HERMSDORF, AND ALBRECHT-FRANK, or BERLIN,

GERMANY, ASSIGNORS TO GENERAL ELECTRIC COMPANY.A CORPORA- ,"IION OF NEW YORK.

Specification of Letters Patent.

Iatented June 4, 1907.

' Applica-tion filed October 17,1906. Serial No. 339,352-

To all whom it may concern:

Be it known that we, CARL MITTELSTRASS and ALBRECHT FRANK, subjects of the Emror of Germany, residing at Hermsdorf and rlin, Germany, respectively, have invented certain new and useful Improvements in Motor-Controlling Devices of which the following is a specification.

This invention relates to devices for conitrolling electric motor circuits and has for its object the rovision of a device of this character, wh1c upon the occurrence of abnormal conditions in the circuit, will automatically return to a position to protect the motor.

1 Our invention relates more specifically to starting or controlling devices for electric motors in which an auxiliary motor is utilized for the movement of the controlling arm.

In carrying out our invention, we provide 1n connection with an 1m dance in the main motor c rcuit, such as eit er reactance or resistance coils, an auxiliary motor for cutting said coils in and out of circuit. The motor is connected to the" controlling arm in some way, as by gearing, and drives it to the denections are so changed that when normal circuit conditions return, the motor will re verse and return the controlling arm to the startin or protective position.

In t e accom anying drawing we have shown one embo iment of our invention but it should be understood that its particular arrangement is shown really for pur oses of illustration, and that many modi cations thereof will suggest themselves to those skilled in the art without departing from the spirit of 0hr invention.

Referring to the drawing M represents a motor, which in this particular instance, we

have shown as a 3-phase induction motor, al-l thou h the particular t pe of motor used or the-electric circuit in w 'ch it is used are not essential features of our invention. This motor is supplied with current from 3-phase mains 10, 11 and 12, a switch 13 being provided in the main circuit. In circuit with the rotor of the motor are the impedances 14,

15 and 1.6, one for each phase, contacts being provided for cutting out sections of the impedance proportionally and consecutively. A controlling arm 17 is pivoted at 18 and is arranged to co-operate with these contacts to cut out the resistance in the usual way, while an auxiliary motor M has its rotor geared to thearm 17 by a worm 19. The main motor circuit is opened and closed by means of an electromagnetic switch S having a core 26 This armature has con.- nected therewith the contact bars 22 and 23 which are insulated from each other and from the armature proper. This switch is arranged so as to bridge contacts 24 and 25 on one side and contacts 26 and 27 on the other, so as to close the main motor circuit, and auxiliary contacts 28, 29, 3.0 and 31 are arranged to control the circuitv of the auxiliary motor as well as the circuit ofthe energizing coils of the switch S. When the switch is raised to its u per position, the auxiliary contactsv on eadh side are bridged, while in its lower position, it bridges the auxiliary contacts 32 and 33 for reversingthe auxiliary motor. The energizing coils 34, 35 and 36 are controlled by a switch 37 which isspringpressed to an open position by a spring 38. In its starting or initial position, the arm 17 holds the switch v37 closedby means of a finger 39, engaging the end of the switch arm," but as soon as it leaves this pos'ition,'the

switch will automatically open. A second switch 40, preferably hand+operated, is pro' vided to control the circuit-of the switch coils.

' The arrangement of the circuits is as follows: When the switch 13 is closed, the current passes from main 11 through conductor 41, switch 37 conductor 42, switch 40 through the energizing windin 35 and thence through the-windings 34 an 36, returning from the former through the switch 40, conductor 43, switch 37 and conductor 44, and

from the latter through conductor 45. These coils being energized, armature 21' is drawn up to core 20, closing the main motor circuit as follows: from main 10 to contact 24, contact bar 22, contact 25 and conductor 46 to the stator of the motor, returning through conductor 47, contact 26, contact bar 23, Contact 27 to main 11 and through conductor 48 to main 12. The'auxiliary motor is likewise energized as follows: from main 10 and contact 24 to contact 29 through contact her 22 thence through conductor &9 through auxiliary motor itifl'returniug through conductors 50 and 51 to mains l2 and ll re spectively, the latter by Way of contact 30, bar 23 and contact :27. The oiuitilicr motor thus being energized, the crrn is revolved in a counter-clockwise direction, cutting out sections of the impedance. As soon as the arm l7 leaves its initial position the switch 37 is opened. This would. ordinarily deenergize the coils 34, 35 and 36 but the circuits of these coils are in the meantime completed by contact bars 22 and The circuit of these coils Will then he as follows: from contact 24, bar 22, contact 28, conductor 52, switch 40, windings 34 and 35, conductor,

53, switch 4:0, conductor 5%, contests 31. and 27 back to meinll. The current also passes through Winding 36 thence hack to in 12 through. coniluct'or 45. The motor will thus continue to run. until stoppecl in some manner as through the ogenc oi the operator, and the controlling arm 1'? Will rest in the desirecl position. i If new, there is a failure of voltage on the line, coilsS i, 35 and 36 Will be de-energized and the armature 21 Will drop, breaking the circuit of the energizing coils end also changing the auxiliary motor connections, circuit being made through contacts 32 and 33 instead of tiuough contacts 2% and 30. tahlishccl, armature 21 will not be attracted hut the auxiliary motor will he energized. in c. direction so as to reverse it, the current passing through contact 24: to contact thence through the cross connection to contact 30 and conductor 51, returning conductors 49 and 50, the latter conductor passingto main 12 through conductor to, 1

While conductor 49 passes from contact 29 through the cross connection to contact thence by contact bar 23 end contact 27 to main 11. The motor thus starts in a reverse direction ontl continues until it reaches the starting position. When starting or initial position is reached, the switch S7 closed and the coils 34;, and 36 ere again energized. and armature attracted. The motor connections are thus again changed, and the arm 17 is rotated into counter-clock- Wise direction as before.

g It Will thus be seen that the motor is protested irom'damage due to abnormal circuit conditions. When the circuit opened by failure of voltage, it cannot be oga-inlclosed until the controlling srrn is placed. in its initial position, and all the impedance is in circuit. The means whereby We have ac complisherl this result are extremely simple and positive, While at the same time being thoroughly efficient and reliable.

Many modifications Wlll suggest themselves to those skilled in the art but it should ,be

' imiierstoocl that the construction which We i fhen the line voltage is re-es' comg irising an impedance,

have shown. is merely itjuia'sl, and. our iuvention is only limited by toe s: of the claims annexed hereto.

What We claim as or by Letters Patent oi the L torl States,

1. The combination v' .1 on illrlli tor circuit oi a controlling device comprising an impedance, tor for varying the same, trolled by the movement of sold (is reversing saicl auxiliary motor.

The combination with an electric inotor circuit of means for controlling the same comprising an auxiliary motor, curl moons for automatically changing the comicctions thereof upon failure of voltage in the circuit, so as to reverse the auxiliary motor upon the return of voltage. 1

3. The combination with on electric motor circuit of means for controlling the same comprising an auxiliary motor, an. electromagnetic switch in the main motor circuit, and connections whereby said o itch autometically reverses said auxiliary motor.

The combination with an electr motor circuit of. means for controlling the some comprising an impedance, an electric motor for varying the same, and means for automatically changing the connections thereof upon failure cit-voltage so e to secure as to reverse the seitl motor upon the return of voltage.

5-. T he combination. with en el circuit of means for centrethe ri'nieens iosoul me of voltage so as to reverse the return of voltage.

6. The combination with on electric mo tor circuit of means for controlling the some comprising an. auxiliary motor, on electric ally controlled device for closing the main motor circuit, and means whereby said. device .Jllfi connections of sold auxil- 8. Tee combination wi on electric motor circuit of means ior con A g the comprising an auxiliary tiotor, an electromagnetic device for automatically opening said motor circuit, and means controlled by the movement of said device whereby the connections or said auxiliary motor ere 1. he cor'hination with electric 1X10" iury motor cpori ullQ lauuz or tsge so as v to reverse the same upon the row. 1 or voltags.

upon the opening of said main motor circuit so as to reverse the motor upon the closing of the main circuit.

9. The combination with an electric motor circuit of means for controlling the same comprising an auxiliary motor, an electromagnetic switch for opening and closing said main motor circuit, and connections whereby said auxiliary motor will run in one direction when the switch is open and in the opposite direction when the switch is closed.

10. The combination with an electric motor circuit of means for controlling the same comprising an auxiliary motor, an electrowhereby said auxiliary motor will run in one direction when the switch is open and 111 the opposite direction when the switch is closed. 20

in witness whereof, I have hereunto set my hand this third day of October, 1906.

CARL MITTELSTRASS. ALBRECHT FRANK.

Vifitnesses: JULIUS RINNLAND, KARL KREKEBEN. 

